Modified baculovirus system for high expression of Bombyx mori bidensovirus NS1 in silkworm / 生物工程学报

To improve the expression of heterologous genes using baculovirus expression system, we constructed a novel shuttle vector based on the Bm-Bacmid. In the Bm-Bacmid, partial sequences of Chitinase and Cystein Protease were replaced with a tandem cassette of Cm and egfp through homologous recombination. Bombyx mori bidensovirus (BmBDV) ns1 under the control of polyhedrin promoter was inserted into the modified Bm-bacmid by transposition. For comparison, BmBDV ns1 under the control of polyhedrin promoter was also cloned in the wild type Bm-bacmid. The resulting Bm-bacmids were transfected into the cultured BmN cells to prepare recombinant virus to infect silkworms for expression of BmBDV ns1. Total proteins of hemocyte from infected silkworms were subjected to Western blotting and ELISA analysis. The yield of BmBDV NS1 1 with the modified vector was three times as much as that with the unmodified vector. The method to improve the yield of BmBDV NS1 in silkworms will facilitate the function and three-dimensional structure study of BmBDV NS1.

Research Progress in Black Queen Cell Virus Causing Disease / 病毒学报

In nature, honeybees are the most important pollinators. They play a vital role in both protecting the diversity of natural ecosystems, and maintaining the yield-improving effects of agroecosystems. But in recent years, epidemic disease in bees has caused huge losses. Black Queen Cell Virus (BQCV) is a bee pathogen that was first reported in 1955. It mainly infects bee larvae and pupae, making their bodies turn dark and black, and causing a massive decrease in the bee population. More specifically, the virus makes the exterior of the cell walls in the larvae and pupae turn black. BQCV is a seasonal epidemic, spread by means horizontal and vertical transmission, and is often unapparent. BQCV not only infects a variety of bee species, but also spiders, centipedes and other arthropods. It can also be coinfected with other honeybee viruses. In recent years, research has shown that the Nosema intestinal parasite plays an important role in BQCV transmission and bees carrying Nosema that become infected with BQCV have increased mortality. Here we summarize current research on the incidence, prevalence, geographical distribution and transmission of BQCV.

First isolation of quang binh-like virus from mosquitoes in China / 病毒学报

This study aims to investigate the distribution patterns of mosquito-borne viruses in Menghai County, Xishuangbanna Prefecture, Yunnan Province, China and to provide evidence for the prevention and control of mosquito-borne diseases. Mosquito samples were collected using mosquito lamps. Viruses were isolated from the samples by cell culture, and the isolates were identified by RT-PCR. The genomes of isolates were sequenced for phylogenetic analysis. In July 2012, a total of 1468 mosquitoes were captured in Daluo Town of Menghai County; they were divided into 32 pools, including Culex tritaeniorhynchus (28 pools, 1383 mosquitoes), Culex quinquefasciatus (2 pools, 66 mosquitoes), and Anopheles (2 pools, 19 mosquitoes). Golden hamster kidney cells (BHK-21) and Aedes albopictus cells (C6/36) were used for virus isolation. The results showed that C6/36 cells were susceptible to two isolates recovered from Culex tritaeniorhynchus (BNDL1205 and BNDL1227), with marked cytopathic effect (CPE) of cell fusion. By contrast, the two isolates could not cause CPE in BHK-21 cells. RT-PCR was performed for the two isolates using the flavivirus-specific primers FU2/cFD3, and a 800-bp amplicon was obtained from both of them. Phylogenetic analysis showed that the two isolates shared the same evolutionary branch with the Quang Binh virus (QBV) strain VN180, which had been isolated from Vietnam, with nucleotide sequence homologies of 83.4% and 82.9%, respectively. However, there existed relatively large differences in nucleotide sequence between them and other Culex flavivirus strains previously isolated in China and other regions. In light of the similarity between the two isolates and QBV, BNDL1205 and BNDL122 were referred to as Quang Binh-like virus, which were first reported in China.

Isolation and primary identification of viruses in mosquitoes in the south of Xinjiang / 中华预防医学杂志

<p><b>OBJECTIVE</b>To isolate viruses from mosquitoes in the south of Xinjiang and identify these viruses primarily.</p><p><b>METHODS</b>A total of 13 491 mosquitoes were collected in the south of Xinjiang from Jul to Aug, 2005. These mosquitoes were divided into 130 groups and grinded respectively. The supernates were inoculated in C6/36 and Vero cells. Viruses isolated were detected, the genomic nucleic types by electrophoresis of viral genomes and the morphologies observed under electronmicroscope.</p><p><b>RESULTS</b>All 42 viruses were isolated, which caused CPEs on C6/36 but not on Vero cells. 27 viruses showed similar genomic profiles with 12 dsRNA segments. 1 virus displayed genomic profile with 10 dsRNA segments. 5 viruses took on similar genomic profiles with about 4 kbp DNA band. 9 viruses did not get any taxonomy information. Electromicroscopic pictures of these viruses revealed that above four types of viruses had distinguished morphologies indicating different virus species.</p><p><b>CONCLUSION</b>There should be several virus species in the mosquitoes in the south of Xinjiang. dsRNA virus with 12 genomic segments should play analysis a predominant role in the south of Xinjiang.</p>

Ubiquitin-proteasome pathway and virus infection / 生物工程学报

Ubiquitin is highly conserved 76 amino acid protein found in all eukaryotic organisms and ubiquitin-proteasome pathway (UPP) plays a very important role in regulated non-lysosomal ATP dependent protein degradation. This pathway participates in or regulates numerous cellular processes, such as selective protein degradation, cell cycle progression, apoptosis, signal transduction, transcriptional regulation, receptor control by endocytosis, immune response and the processing of antigens. Nevertheless, roles of UPP in virus infection are only beginning to be clarified. Ubiquitin homology has also been found in insect viruses. All viral ubiquitin genes encode an N-terminal ubiquitin sequence and 3-256 amino acids C-terminal peptides. Most of the residues known to be essential for ubiquitin function have been conserved in the viral variant. In Autographa californica nucleopolyhedrovirus (AcMNPV), viral ubiquitin is attached to the inner surface of budded viron membrane by a covalently linked phospholipid and is not essential for viral replication. Currently, insect viruses are the only viruses known to encode ubiquitin. However, ubiquitin also plays a role in the life cycle of other viruses. Host ubiquitin molecules have been found in some plant viruses and other animal viruses. Additionally, Africa swine fever virus (ASFV) encodes a ubiquitin-conjugating enzyme (E2) and a putative causal link between human immunodeficiency virus type 1 (HIV-1) and ubiquitin was established by showing that depletion of the intracellular pool of free ubiquitin inhibits the virus budding. Further analyses indicated that many retroviruses proteins which are required for efficient pinching off the virus bud contain a late domain. The core element of the late domain is a proline-rich motif (PPXY) which mediates the late domain to be ubiquitinated by cellular proteins. Recently, it has been shown that many retroviruses have developed mechanisms to escape the cellular immune response, to facilitate virus replication and to promote virus assembly and budding via host UPP.

Triatoma patagonica (Hemiptera, Reduviidae), a New Host for Triatoma virus

Previous authors demonstrated that Triatoma virus (TrV) is able to infect several species of triatomines when injected with viral inoculum obtained from its original host, T. infestans. Both vertical (transovarian) and horizontal (faecal-oral) mechanisms of viral transmission were also described. In this paper we report the experimental TrV infection of a wild species from southern Argentina, T. patagonica. The inoculum consisted of clarified gut contents of infected T. infestans rubbed on the chicken skin whereupon T. patagonica individuals were fed. The results demonstrate that this is another potential host for the virus, and that the oral route is also effective for experimental interspecific infections

Animales peligrosos por producir venenosos y secreciones de defensa / Dangerous animals to produce poisonous and secretions of defense

El veneno es una sustancia que causa una lesion al entrar en el cuerpo, dependiendo de la cantidad y estado físico de la persona esta pueda tener consecuencias muy severas en la salud del afectado.

Direct methods for detecting picorna-like virus from dead and alive Triatomine insects

In this work we report four different destructive and non-destructive methods for detecting picorna-like virus particles in triatomines. The methods are based on direct observation under transmission electron microscope and they consist of four ways to prepare samples of presumable infected material. The samples are prepared processing dead or alive insect parts, or even dry or fresh insect feces. The methods can be used as analytical or preparative techniques, for quantifying virus infection and checking virus integrity as well. In this work the four methods are applied in order to detect Triatoma virus (TrV) particles in T. infestans colonies.